1. Field of the Invention
The present invention generally relates to door closers, and more particularly to an adjustable hydraulic door closer wherein the opening cycle as well as the closing cycle of the door connected to the door closer can be fully controlled by manipulation of hydraulic fluid within the closer.
2. Description of the Related Art
A number of door closing mechanisms are available that both urge a door to a closed position, and slow the closing speed of the door to prevent the door from slamming into the door frame under force of the closing mechanism. Door closers are known for swinging doors having a spring actuated closing force with a hydraulic pot within the device that retards the closing speed. These closers have valve passage systems for passing hydraulic fluid in order to control the speed of door closing. Such door closers are disclosed in U.S. Pat. Nos. 4,064,589 and 3,246,362.
Some door closers have adjustable spring tension in order to increase or decrease the closing resistance or load provided by the door closer. An example of one such door closer is disclosed in U.S. Pat. No. 5,666,692.
One object of the present invention is to provide a door closer that has a compact and rugged structure. Another object of the present invention is to provide a door closer that utilizes a spring or springs mounted for compression within a housing of the closer. A further object of the present invention is to provide a door closer wherein the opening cycle of the door connected to the mechanism can be fully controlled. A still further object of the present is to provide a door closer wherein the closing cycle of the door that is connected to the closer can also be fully controlled. Another object of the present invention is to provide a door closer wherein the opening cycle control is accomplished by a novel arrangement of fluid passages and valves within the mechanism. An additional object of the present invention is to provide a door closer wherein the opening cycle is adjustable from an exterior of a closer. A still further object of the present invention is to provide a door closer wherein both the door opening and closing cycles are adjustable.
These and other objects, features and advantages of the present invention are achieved by a novel oil passageway arrangement within the door closer mechanism. In one embodiment, a hydraulic backcheck valve system for controlling an opening cycle of a door closer has a housing with an interior chamber, at least one cylinder, and a piston that can reciprocate between a door closing stroke and a door opening stroke within the cylinder. One side of the piston faces a variable volume chamber in the cylinder and an opposite side of the piston faces the interior chamber of the housing. The backcheck valve system has a fluid passage with a port in fluid communication with the cylinder and an opening in fluid communication with the interior chamber of the housing. The port is blocked by the piston during at least part of the door opening stroke. A one-way valve is disposed in fluid communication with the fluid passage and permits fluid to flow freely during a closing cycle of the door closer and prevents fluid flow from the second passage during the opening cycle. A backcheck valve is disposed in fluid communication with the passage and with the variable volume chamber. The backcheck valve permits metered fluid flow from the second passage to the variable volume chamber during the opening cycle to control the opening cycle.
In one embodiment, the port permits fluid to bypass the backcheck valve when the piston does not block the port during the opening cycle.
In one embodiment, the one-way valve assembly is a ball check valve assembly having a ball and a valve seat.
In one embodiment, the backcheck valve is an adjustable needle valve having a tool receiving head and a valve stem.
In one embodiment, the tool receiving head is accessible from an exterior of the housing to permit adjustment of the needle valve in order to vary a rate of the metered fluid flow for fluid that flows through the needle valve to adjust a resistance of the opening cycle.
In another embodiment of the invention, a door closer defining a door opening and a door closing cycle has a housing having an interior, at least one cylinder within the housing, and at least one piston that can reciprocate between a door closing stroke and a door opening stroke within the at least one cylinder. The at least one piston divides the interior into first and second chambers. A first passage is in fluid communication with the first chamber. A second passage has an opening in fluid communication with the second chamber and a second port in fluid communication with the at least one cylinder. The second port is blocked by the piston during at least part of the door opening stroke. A first one-way valve is in fluid communication with the first and the second passages. The one-way valve assembly permits fluid flow from the first passage to the second passage and prohibits fluid flow from the second passage to the first passage. A backcheck valve is in fluid communication with the first and the second passages and permits metered fluid flow from the second passage to the first passage. Fluid can bypass the backcheck valve through the port when the at least one piston does not block the port during the door opening stroke of the opening cycle.
In one embodiment, the door closer also has a biasing mechanism for biasing the at least one piston in a direction of the door closing stroke. In one embodiment, the biasing mechanism is a spring.
In one embodiment, the door closer also has a pair of the cylinders within the housing and a pair of the pistons, one each received in a corresponding one of the cylinders. A pair of the second ports each provide fluid communication between the second passage and a corresponding one of the cylinders.
In one embodiment, the first chamber is a variable volume chamber defined within the cylinder and faces one side of the at least one piston. The second chamber is an interior chamber of the housing and faces an opposite side of the pistons.
In one embodiment, the door closer also has a first port providing fluid communication between the first passage and the first chamber, and a third passage having a third port providing fluid communication between the third passage and the first chamber. The third port is positioned between the first and the second ports in the at least one cylinder. The third port is blocked by the at least one piston during at least part of the door closing stroke.
In one embodiment, the door closer also has a latch speed valve providing metered fluid flow between the first and the third passages when the third ports are blocked during the closing stroke, and a closing speed valve providing metered fluid flow between the first and the third passages when the third ports are not blocked during the closing stroke.
In one embodiment, the door closer also has a second one-way check valve disposed within the first passage between the closing speed valve and the latching speed valve. The second one-way check valve permits fluid flow from the closing speed valve to the latching speed valve within the first passage and prohibits fluid flow from the latching speed valve to the closing speed valve within the first passage.
In one embodiment, the second one-way check valve is a ball check valve with a valve seat and a ball. The ball is restrained in one direction of the first passage by the valve seat and in an opposite direction of the first passage by a valve stem of the latching speed valve.
In one embodiment, the backcheck valve is a needle valve with a valve stem and a tool receiving head on one end of the valve stem for receiving a tool that can adjust the metered flow rate of the backcheck valve. In one embodiment, the tool receiving head of the backcheck valve is accessible from an exterior surface of the housing.
In another embodiment of the invention, a one-way valve assembly has a fluid passage having opposed ends and a ball received in the fluid passage between the opposed ends. A valve seat is received in the fluid passage and is positioned to prevent movement of the ball toward one of the opposed ends. A valve stem of another valve assembly passes through the fluid passage, whereby the ball is prevented from moving toward the other of the opposed ends by the valve stem and is free to move within the fluid passage between the valve stem and the valve seat.
These and other objects, features and advantages of the present invention will become apparent upon reading the detailed description and accompanying drawing figures. Specific embodiments are described herein and are shown in the drawing figures. Changes and modifications can be made to the specific embodiments disclosed herein and yet fall within the scope of the present invention. The embodiments described and shown in the drawings are provided in order to illustrate the present invention and not in any way to limit the present invention.